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Analytica Chimica Acta Aug 2024Arsenosugars are the predominant species of arsenic in most seaweed. The analysis of these compounds is hampered by the lack of calibration standards needed in their...
Arsenosugars are the predominant species of arsenic in most seaweed. The analysis of these compounds is hampered by the lack of calibration standards needed in their unambiguous identification and quantification. This affects the availability of reliable information on their potential toxicity, which is scarce and controversial. Knowing the potential of centrifugal partition chromatography (CPC) as a preparative separation technique applied to a number of natural compounds, the aim of this work is to investigate the feasibility of CPC in the case of isolation and purification of arsenosugars from algae extracts. Several biphasic solvents systems have been studied to evaluate the distribution of the As species. Given the physical characteristics of these compounds, the presence of strong acids, the formation of ionic pairs or the presence of salts at high ionic strength have been considered. System 1-BuOH/EtOH/sat.(NH)SO/water at a volume ratio 0.2:1:1:1 originates adequate distribution constants of analytes that allows the required separation. The total arsenic content and the arsenic speciation of the eluted solutions from CPC were analyzed by ICP-MS and IC-ICP-MS, respectively. The developed CPC procedure allows us to obtain of the three arsenosugars with a purity of 98.7 % in PO-Sug, 90.4 % in SO-Sug and 96.1 % in SO-Sug.
Topics: Countercurrent Distribution; Arsenates; Seaweed; Monosaccharides
PubMed: 38879213
DOI: 10.1016/j.aca.2024.342814 -
Environment International Jun 2024Mercury is a highly toxic trace metal that can accumulate in aquatic ecosystems and when resent at high concentrations can pose risks to both aquatic life and humans...
Mercury is a highly toxic trace metal that can accumulate in aquatic ecosystems and when resent at high concentrations can pose risks to both aquatic life and humans consuming contaminated fish. This research explores the use of the metalloregulatory protein MerR, known for its high affinity and selectivity toward mercury, in a novel application. Through a cell surface engineering approach, MerR was displayed on cells of green alga Chlamydomonas reinhardtii. A hydroxyproline-rich GP1 protein was used as an anchor to construct the engineered strains GP1-MerR that expresses the fluorescent protein mVenus. The surface engineered GP1-MerR strain led up to five folds higher Hg accumulation compared to the WT strain at concentration range from 10 to 10 M Hg. The binding of Hg via MerR was specific and did not get significantly affected by major freshwater water quality variables such as Ca and dissolved organic matter. The presence of other trace metals (Zn, Cu, Ni, Pb, Cd) in a same concentration range even resulted in 30-40 % increase in the accumulated Hg. Further, the engineered cells also demonstrated the ability to accumulate Hg from the water extracts of the Hg-contaminated sediment samples. These results demonstrate a novel approach utilizing the cell surface display system in C. reinhardtii for its potential application in bioremediation.
PubMed: 38878502
DOI: 10.1016/j.envint.2024.108813 -
Marine Pollution Bulletin Jun 2024Cyanobacteria harmful algal blooms (CHABs) are a growing water quality problem in the upper San Francisco Estuary (California), also known as the Sacramento-San Joaquin...
Cyanobacteria harmful algal blooms (CHABs) are a growing water quality problem in the upper San Francisco Estuary (California), also known as the Sacramento-San Joaquin Delta. We conducted cyanobacteria and cyanotoxin monitoring from 2020 to 2023, which spanned California's driest consecutive 3-year period and one of the wettest years on record (2023). To assess the impact of CHABs over this range of hydrologic conditions, we monitored invasive Asian Clams (Corbicula fluminea) for microcystin contamination and used molecular tools (qPCR and sequencing) to characterize cyanobacteria in the water column. We also used solid phase adsorption toxin tracking (SPATT) samplers to track microcystins (MCs) and other cyanotoxins in 2023. During the drought years, record breaking MCs, in excess of 1000 μg/L, were documented in water grab samples and Asian clams also accumulated higher MCs relative to the wet year. However, MCs were present in Asian clams during the entire study period. SPATT's confirmed MC presence during wet 2023 and sequencing results corroborated the integrative sampler findings. Yet, no MC was detected in water grab samples at our primary sampling sites during the drought year of 2022 or the wet year of 2023. This highlights the importance of using multiple sampling modalities to provide a more accurate assessment of MC contamination, especially in large estuaries where traditional discrete monitoring can easily miss episodic and transient CHAB events.
PubMed: 38878417
DOI: 10.1016/j.marpolbul.2024.116585 -
Ecotoxicology and Environmental Safety Jun 2024Early cyanobacterial blooms studies observed that exposure to blue-green algae led to fish gills impairment. The objective of this work was to evaluate the toxic...
Early cyanobacterial blooms studies observed that exposure to blue-green algae led to fish gills impairment. The objective of this work was to evaluate the toxic mechanisms of exudates of Microcystis aeruginosa (MaE) on fish gills. In this study, the toxic mechanism of MaE (2×10 cells/mL) and one of its main components phytosphingosine (PHS) with two concentrations 2.9 ng/mL and 145 ng/mL were conducted by integrating histopathology, biochemical biomarkers, and transcriptomics techniques in Sinocyclocheilus grahami (S. grahami) for 96 h exposure. Damaged gill tissue with epithelial hyperplasia and hypertrophy, remarkable Na/K-ATPase (NKA) enzyme activity, disrupted the redox homeostats including lipid peroxidation and inflammatory responses were observed in the fish of MaE exposure group. Compare to MaE exposure, two concentrations of PHS exposure appeared to be a trend of lower degree of tissue damage, NKA activity and oxidative stress, but induced obviously lipid metabolism disorder with higher triglycerides, total cholesterol and total bile acid, which might be responsible for inflammation responses in fish gill. By transcriptome analysis, MaE exposure were primarily enriched in pathways related to gill function and immune response. PHS exposure, with higher number of differentially expressed genes (DEGs), were enriched in Toll-like receptor (TLR), Mitogen-Activated Protein Kinase (MAPK) and NOD-like receptor protein 3 (NLRP3) pathways. We concluded that MaE and PHS were induced the inflammatory responses, with oxidative stress-induced inflammation for MaE exposure but lipid metabolism disorder-induced inflammation for PHS exposure. The present study provided two toxin-induced gill inflammation response pathways under cyanobacterial blooms, which could be a scientific basis for the ecological and health risk assessment in the aquatic environment.
PubMed: 38878336
DOI: 10.1016/j.ecoenv.2024.116587 -
Marine Environmental Research Jun 2024Invasive species that outcompete endemic ones and toxic harmful algae that cause algal blooms threaten marine resources like fisheries, aquaculture, and even tourism....
Invasive species that outcompete endemic ones and toxic harmful algae that cause algal blooms threaten marine resources like fisheries, aquaculture, and even tourism. Environmental DNA (eDNA) metabarcoding can help as a method for early alert. In this study, we have analyzed communities inhabiting six lagoons within the Gulf of Lion (northwest Mediterranean Sea) with spatial protection as RAMSAR and Natura 2000 sites. Employing the COI gene as the only metabarcode, we found 15 genera that have caused recognized algal bloom outbreaks in the studied lagoons since 2000. In addition, seven alien invasive species that can pose risks to the rich marine resources of the zone and lagoons were also found. The results found from eDNA are consistent with events of toxic algae blooms before and after the sampling moment and with reported occurrences of the invasive species in nearby Mediterranean areas. Multivariate multiple analysis showed the importance of anthropic pressure in the abundance of these nuisance species. Mitigation actions and routine eDNA metabarcoding in zones of special interest like these fragile French Mediterranean lagoons are recommended for early alert of nuisance species in order to plan timely management actions.
PubMed: 38875900
DOI: 10.1016/j.marenvres.2024.106601 -
Genome Biology and Evolution Jun 2024In flowering plants, euchromatic transposons are transcriptionally silenced by RNA-directed DNA methylation (RdDM), a small RNA-guided de novo methylation pathway. RdDM...
In flowering plants, euchromatic transposons are transcriptionally silenced by RNA-directed DNA methylation (RdDM), a small RNA-guided de novo methylation pathway. RdDM requires the activity of the RNA Polymerase (Pol) IV and V, which produce small RNA precursors and non-coding targets of small RNAs, respectively. These polymerases are distinguished from Pol II by multiple plant-specific paralogous subunits. Most RdDM components are present in all land plants, and some have been found in the Charophytic green algae (CGA), a paraphyletic group that is sister to land plants. However, the evolutionary origin of key RdDM components, including the two largest subunits of Pol IV and Pol V, remains unclear. Here we show that multiple lineages of CGA encode a single-copy precursor of the largest subunits of Pol IV and Pol V, resolving the two presumed duplications in this gene family. We further demonstrate the presence of a Pol V-like C-terminal domain, suggesting that the earliest form of RdDM utilized a single Pol V-like polymerase. Finally, we reveal that CGAs encode a single CLSY/DRD1-type chromatin remodeling protein, further supporting the presence of a single specialized polymerase in CGA.
PubMed: 38874416
DOI: 10.1093/gbe/evae119 -
Food Science & Nutrition Jun 2024Rhamnan sulphate (RS) is a sulphated polysaccharide found in green algae such as that exhibits various biological functions, including anticoagulant, antitumour,...
Rhamnan sulphate (RS) is a sulphated polysaccharide found in green algae such as that exhibits various biological functions, including anticoagulant, antitumour, antiviral, and anti-obesity properties. In our previous clinical trial, we demonstrated that RS intake improves constipation. However, no specific bacteria showed a significant ( < .05) change. Notably, these results were obtained after a short RS inoculation period of only 2 weeks. In the present study, to evaluate the long-term effects of RS on the gut microbiota, we orally administered RS to BALB/c mice for 11 weeks, analyzed their blood biochemical data, and performed 16s rRNA-sequencing. Oral administration of RS increased body weight with increased food intake, whereas plasma total cholesterol and fasting plasma glucose levels decreased. RS-fed mice showed lower fasting insulin levels ( < .1) and decreased homeostatic model assessment for insulin resistance (HOMA-IR, < .0001), suggesting that RS improved insulin resistance. In the feces of mice, the amounts of acetic and propionic acids increased. In the gut microbiota, predictive metagenomic profiling using the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) revealed functional alterations in Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways in RS-fed mice. Corresponding to the blood glucose-lowering effect, the glycolysis and tricarboxylic acid (TCA) cycle pathways were activated. In addition, the Firmicutes/Bacteroides (F/B) ratio, which may be associated with various health outcomes, was also reduced. These results suggest that the blood glucose-lowering effect, improvement in insulin resistance, and lipid-lowering effect of RS may be due to changes in the intestinal microbiota.
PubMed: 38873438
DOI: 10.1002/fsn3.4100 -
Frontiers in Microbiology 2024Fungi possess well-developed secondary metabolism pathways that are worthy of in-depth exploration. The One Strain Many Compounds (OSMAC) strategy is a useful method for...
Fungi possess well-developed secondary metabolism pathways that are worthy of in-depth exploration. The One Strain Many Compounds (OSMAC) strategy is a useful method for exploring chemically diverse secondary metabolites. In this study, continued chemical investigations of the marine red algae-derived endophytic fungus 2021CDF-3 cultured in PDB media yielded six structurally diverse indole derivatives, including two new prenylated indole alkaloids asperinamide B () and peniochroloid B (), as well as four related derivatives (compounds - and ). The chemical structures of these compounds, including the absolute configurations of and , were determined by extensive analyses of HRESIMS, 1D and 2D NMR spectroscopic data, and TDDFT-ECD calculations. Compound was found to possess an unusual 3-pyrrolidone dimethylbenzopyran fused to the bicyclo[2.2.2]diazaoctane moiety, which was rare in previously reported prenylated indole alkaloids. cytotoxic experiments against four human tumor cell lines (HeLa, HepG2, FADU, and A549) indicated that strongly inhibited the FADU cell line, with an IC value of 0.43 ± 0.03 μM. This study suggested that the new prenylated indole alkaloid is a potential lead compound for anti-FADU drugs.
PubMed: 38873167
DOI: 10.3389/fmicb.2024.1400803 -
The Science of the Total Environment Jun 2024Soil bacterial communities play a critical role in shaping soil stability and formation, exhibiting a dynamic interaction with local climate and soil depth. We employed...
Soil bacterial communities play a critical role in shaping soil stability and formation, exhibiting a dynamic interaction with local climate and soil depth. We employed an innovative DNA separation method to characterize microbial assemblages in low-biomass environments such as deserts and distinguish between intracellular DNA (iDNA) and extracellular DNA (eDNA) in soils. This approach, combined with analyses of physicochemical properties and co-occurrence networks, investigated soil bacterial communities across four sites representing diverse climatic gradients (i.e., arid, semi-arid, Mediterranean, and humid) along the Chilean Coastal Cordillera. The separation method yielded a distinctive unimodal pattern in the iDNA pool alpha diversity, increasing from arid to semi-arid climates and decreasing in humid environments, highlighting the rapid feedback of the iDNA community to increasing soil moisture. In the arid region, harsh surface conditions restrict bacterial growth, leading to peak iDNA abundance and diversity occurring in slightly deeper layers than the other sites. Our findings confirmed the association between specialist bacteria and ecosystem-functional traits. We observed transitions from Halomonas and Delftia, resistant to extreme arid environments, to Class AD3 and the genus Bradyrhizobium, associated with plants and organic matter in humid environments. The distance-based redundancy analysis (dbRDA) analysis revealed that soil pH and moisture were the key parameters that influenced bacterial community variation. The eDNA community correlated slightly better with the environment than the iDNA community, whereas the iDNA community was more sensitive to changes in soil physicochemical parameters. Soil depth was found to influence the iDNA community significantly but not the eDNA community, which might be related to depth-related metabolic activity. Our investigation into iDNA communities uncovered deterministic community assembly and distinct co-occurrence modules correlated with unique bacterial taxa, thereby showing connections with sites and key environmental factors. The study additionally revealed the effects of climatic gradients and soil depth on living and dead bacterial communities, emphasizing the need to distinguish between iDNA and eDNA pools.
PubMed: 38871316
DOI: 10.1016/j.scitotenv.2024.173846 -
PloS One 2024Mosquito-borne diseases pose a global health threat, with pathogens like Malaria, Dengue fever, and others transmitted by mosquitoes. Our study focuses on evaluating the...
Mosquito-borne diseases pose a global health threat, with pathogens like Malaria, Dengue fever, and others transmitted by mosquitoes. Our study focuses on evaluating the toxicity of genetically engineered mosquito larvicidal algae (Chlamydomonas reinhardtii) to non-target organisms, specifically Zebrafish. We conducted a 90-day experiment, feeding Zebrafish different combinations of larvicidal algae and commercial fish feed. Statistical analysis revealed no significant differences in mortality, allergenicity, or moribundity among groups. Hematology, molecular analysis, and necropsy showed no physiological differences. Our findings indicate that the transgenic algae (TN72.cry11Ba) had no adverse effects on adult Zebrafish or their larvae. This study confirmed the safety of algae on non-target organisms, such as zebrafish.
Topics: Animals; Zebrafish; Larva; Chlamydomonas reinhardtii; Embryo, Nonmammalian; Culicidae; Administration, Oral; Insecticides
PubMed: 38870118
DOI: 10.1371/journal.pone.0303352